Is There a Relationship Between Birth Quartile and Vertical Jump Performance Among Young Male Elite Volleyball Athletes?

Vertical jump is an important skill that influences volleyball performance. In this study, we analyzed the relationship between vertical jump performance and birth quartile of Brazilian male youth volleyball players. We calculated chi-square goodness-of-fit tests to compare the athletes' birthdate distributions in quarters of their birth years (Q1, Q2, Q3, and Q4) according to player age categories (U17, U18, U19, and U21). We calculated one-way ANOVAs to compare spike jump and block jump heights of players born in different quarters of the same year. Overall, we found a relative age effect (i.e., more players with birth dates early in the birth year) in U17 (p < .001), U18 (p < .001), U19 (p < .001), and U21 (p = .04). Regarding vertical jump performance, U18 athletes born in Q2 reached higher spike jump heights (p = .006) and block jump heights (p = .002) than athletes born in Q4, and U19 athletes born in Q1 reached higher block jump heights than athletes born in Q3 (p = .049). There were no significant differences in vertical jump performance across birth quartiles among U17 and U21 athletes. Thus, a relative age effect was present in all age categories but not always reflected in vertical jump performance. Volleyball coaches and policymakers are still advised to employ strategies to ensure fairer opportunities for players born later in the year of their eligibility dates, as we found RAE to be sometimes, but not always, related to higher spike or block jump heights even among these older adolescents and young adult athletes.

Upper and Lower Limbs Acute Fatigue Did Not Mitigate Male Trained Air Force Soldiers' Marksmanship.

In this study, we aimed to investigate the impact of acute fatigue on pistol shooting performance among Air Force marksmen. We compared the accuracy, precision, speed-accuracy trade-off, shooting cycle time, and hits on a silhouette target among 12 Brazilian Air Force servicemen (M age = 21.5, SD - 1.6 years) under both fatigue and non-fatigue conditions in a crossover design. In the fatigued condition, the participants performed a fatigue protocol composed of side runs, vertical jumps, push-ups, running, and burpees exercises before shooting. Participants performed the countermovement jump and the plyometric push-ups tests on a contact mat before and immediately after the fatigue protocol to compare the heights achieved pre- and post-fatigue. Paired t-tests showed a significant performance reduction of 34.36% and 40.02% for the countermovement jump and plyometric push-ups, respectively, indicating that participants were fatigued in their lower and upper limbs. In the non-fatigued condition, no exercise was performed before shooting. Results indicated no significant differences between conditions on shooting precision (p = .125; ES: .54), speed-accuracy trade-off (p = .261; ES = .33), hits within the silhouette (p = .167; ES = .41), or shooting cycle times (p = .868; ES = .05); but accuracy was greater (p = .025; ES: .54) when fatigued. We concluded that overall shooting performance was not impaired by physical fatigue, and shooting accuracy appeared to be improved. Perhaps physical fatigue was not enough to impair shooting accuracy in this young adult group, as accuracy decline is expected instead when shooters are in an exhausted state. Further research is needed to confirm these findings and test this presumption.

Does Relative Age Effect Exist in Paralympic Sport? A Study With Brazilian Paralympic Swimmers.

A Relative Age Effect (RAE), by which young athletes with birthdates early in a calendar year have experienced a team selection advantage that persists throughout their careers, has been found to be prevalent in many sports. However, this phenomenon has not been investigated in the Paralympic sports context. Thus, we aimed to investigate the prevalence of RAE among male and female Brazilian Paralympic swimmers. Data from 694 ranked athletes were collected from the 2021 Brazilian Paralympic Swimmers National rankings. Athletes' birthdates were divided into four quarters (Q1, Q2, Q3, and Q4) according to their month of birth. Chi-Square (χ2) goodness-of-fit tests were used to compare the observed and expected distributions of athletes born in each quarter, based on sex (male and female), impairment type (physical, visual, and intellectual), and swim stroke competition (freestyle, medley, backstroke, butterfly, and breaststroke). The observed birthdates distributions were different from expected in males (χ2 = 11.647; p = 0.009) and females (χ2 = 8.899; p = 0.031), for athletes with physical impairments (χ2 = 10.443; p = 0.015); and for athletes who competed in freestyle (χ2 = 16.683; p = 0.001), medley (χ2 = 12.343; p = 0.006) and backstroke (χ2 = 8.025; p = 0.045) races. Even though our results demonstrated asymmetric distributions of Brazilian Paralympic swimmers' birthdates in many of the analyses, we could not establish the classical prevalence of athletes born at the beginning of the year that defines RAE. Therefore, the selection process of Brazilian Paralympic swimmers does not seem to be influenced by the athletes' time of birth.

Are relative age effects pervasive in lower competitive tiers of school sports? An investigation of student-athletes from Minas Gerais / Los efectos de la edad relativa son dominantes en los niveles menos competitivos del deporte escolar? Una investigación de estudiantes-deportistas de minas gerais / Os efeitos da idade relativa são pervasivos nos níveis menos competitivos do esporte escolar? Uma investigação de estudantes-atletas de Minas Gerais

Este estudio investigaba el Efecto de la Edad Relativa (EEA) en atletas escolares, según categorías y género. Han sido analizados 1356 jugadores masculinos y 1044 femeninas (de 9 a 17 años) que participaron en competencias escolares en Minas Gerais-Brasil en 2018 y/o 2019 en las categorías Sub-11, Sub-14 y/o Sub-17. Los jugadores fueron divididos en cuartos, de acuerdo con el mes de nacimiento: Q1 (enero-marzo), Q2 (abril-junio), Q3 (julio-septiembre) y Q4 (octubre-diciembre). Se realizaron pruebas de chi-cuadrado para verificar la presencia de EEA. El nivel de significación fue 5%. La distribución observada difirió de la esperada cuando todos los jugadores fueron analizados juntos (p = 0.019; ⍵ = 0.06), y en los hombres, cuando los jugadores fueron analizados por género (p = 0.017; ⍵ = 0.09). En ambos casos se encontró una mayor proporción de jugadores nacidos en los primeros meses del año (p < 0.008). Los resultados indicaron una distribución desigual de nacimientos en la categoría Sub-11 (p < 0.001; ⍵ = 0.25), en la que deportistas nacidos en Q1 y Q2 fueron más frecuentes (p < 0.001). Cuando se analizaron juntos categoría y género, se observó que atletas nacidos en Q1 fueron más frecuentes que los deportistas nacidos en Q3 (p < 0.002) y Q4 (p < 0.001) en la Sub-11, independientemente del género (p < 0.002), pero no en las categorías Sub-14 y Sub-17. Teniendo en cuenta que el deporte escolar puede ser el primer paso para alcanzar mayores niveles competitivos, es importante instruir a los entrenadores sobre el EEA, con el fin de reducir las desigualdades en el acceso al deporte escolar. (AU)

This study investigated the Relative Age Effect (RAE) in school athletes, according to sex and age categories. Birthdates from 1356 male and 1044 female athletes (aged 9 to 17 years) who played scholar competitions in Minas Gerais-Brazil in 2018 and/or 2019 in categories Under-11, Under-14 and/or Under-17 were analyzed. Athletes were divided into quarters according to their month of birth: Q1 (January-March), Q2 (April-June), Q3 (July-September), and Q4 (October-December). Chi-squared tests were performed to verify the presence of RAE. The significance level was set at 5%. The observed distribution was different from expected when all athletes were analyzed together (p = 0.019; ⍵= 0.06), and in males when athletes were analyzed separately by sex (p = 0.017; ⍵= 0.09). Athletes born in the three first months of the year were more frequent in both cases (p < 0.008). The age category analyses indicated uneven distribution of births in Under-11 category (p < 0.001; ⍵= 0.25), where athletes born in Q1 and Q2 were more frequent (p < 0.001). When age category and sex were considered together, it was observed that athletes born in Q1 were more frequent than athletes born in Q3 (p < 0.002) and Q4 (p < 0.001) in the U-11 category regardless of sex (p < 0.002), but not in the Under-14 and Under-17 categories. Considering that school sport can be the first step towards achieving higher competitive levels, it is important to instruct coaches about RAE, in order to reduce inequalities in the access to school sport. (AU)

Este estudo investigou o Efeito da Idade Relativa (EIR) em atletas escolares, de acordo com categorias e sexo. Analisaram-se datas de nascimento de 1356 atletas do sexo masculino e 1044 do sexo feminino (de 9 a 17 anos) que participaram de competições escolares em Minas Gerais-Brasil em 2018 e/ou 2019 nas categorias Sub-11, Sub-14 e/ou Sub-17. Os atletas foram divididos em quartis, de acordo com o mês de nascimento: Q1 (janeiro-março), Q2 (abril-junho), Q3 (julho-setembro) e Q4 (outubro-dezembro). Realizaram-se testes de chi-quadrado para verificar a presença do EIR. O nível de significância adotado foi de 5%. A distribuição observada diferiu do esperado quando todos os atletas foram analisados em conjunto (p = 0.019; ⍵= 0.06), e no sexo masculino, quando os atletas foram analisados por sexo (p = 0.017; ⍵= 0.09). Encontrou-se maior proporção de atletas nascidos nos primeiros meses do ano em ambos os casos (p < 0.008). Os resultados indicaram uma distribuição desigual de nascimentos na categoria Sub-11 (p < 0.001; ⍵= 0.25), onde atletas nascidos nos Q1 e Q2 foram mais frequentes (p < 0.001). Quando a categoria e o sexo foram analisados conjuntamente, se observou que atletas nascidos no Q1 foram mais frequentes que atletas nascidos em Q3 (p < 0.002) e Q4 (p < 0.001) no Sub-11, independentemente do sexo (p < 0.002), mas não nas categorias Sub-14 e Sub-17. Considerando que o esporte escolar pode ser o primeiro passo para alcançar maiores níveis competitivos, é importante instruir os treinadores sobre o EIR, a fim de reduzir as desigualdades de oportunidades de acesso ao esporte escolar. (AU)

Influência do efeito da idade relativa no futsal masculino escolar de Mato Grosso: análise de acordo com a categoria / Influence of the relative age effect on male school futsal in Mato Grosso: a category-based analysis / Influencia del efecto de la edad relativa en el fútbol sala escolar masculino de Mato Grosso: análisis de acuerdo con la categoría

O objetivo deste estudo foi analisar a existência e a influência do Efeito da Idade Relativa (EIR) em estudantes-atletas de futsal masculino de Mato Grosso de acordo com a categoria etária. A amostra foi composta por 486 estudantes-atletas masculinos de futsal de Mato Grosso das categorias A (15 a 17 anos) e B (12 a 14 anos) que disputaram os Jogos Escolares Mato-grossenses e os Jogos Estudantis de Seleções Mato-Grossenses de 2021. Para análise, foram realizados testes qui-quadrado (χ2) de aderência. Os resultados mostraram a presença do EIR na análise geral e nas categorias A e B, com maior representação de atletas nascidos no primeiro trimestre do ano. Conclui-se que o EIR é um fenômeno presente em estudantes-atletas de futsal masculino do estado de Mato Grosso.

The objective of this study was to analyze the existence and influence of the Relative Age Effect (RAE) in male Mato Grosso's futsal student-athletes according to age category. The sample consisted of 486 male futsal student-athletes from Mato Grosso, in categories A (15 to 17 years old) and B (12 to 14 years old) who competed in the 2021 Mato Grosso School Games and the Mato Grosso Student Selections Games. For analysis, chi-square (χ2) goodness of fit tests were performed. Results showed the presence of RAE in the overall analysis and in categories A and B, with a greater representation of athletes born in the first quarter of the year. It is concluded that RAE is a phenomenon present in male futsal student-athletes in the state of Mato Grosso.

El objetivo de este estudio fue analizar la existencia e influencia del Efecto de la Edad Relativa (EER) en estudiantes-atletas de fútbol sala masculino de Mato Grosso de acuerdo con la categoría de edad. La muestra estuvo compuesta por 486 estudiantes-atletas masculinos de fútbol sala de Mato Grosso de las categorías A (15 a 17 años) y B (12 a 14 años) que compitieron en los Juegos Escolares de Mato Grosso y los Juegos Estudiantiles de Selecciones de Mato-Grosso (Brasil) de 2021. Para el análisis, se realizaron pruebas estadísticas de ajuste chi-cuadrado (χ2). Los resultados mostraron la presencia del EER en el análisis general y en las categorías A y B, con una mayor representación de atletas nacidos en el primer trimestre del año. Se concluye que el EER es un fenómeno presente en estudiantes-atletas de fútbol sala masculino del estado de Mato Grosso.

Expectation of Teaching and Self-Controlled KR in Motor Skills Acquisition: Are There Additive Effects?

Purpose: Recent evidence suggests learning a motor skill with the expectation of teaching it enhances motor learning. The mechanisms underlying this effect seem to be similar to those of another motor learning condition, the self-control of knowledge of results (KR). Considering the similarities between the mechanisms that underlie these conditions, we aimed to investigate the learning effects obtained through expected teaching and self-controlled conditions, and whether these effects would be additive. Methods: Participants practiced a dart-throwing task under one of the following conditions: a) expecting to teach the skill; b) controlling the KR request; c) combining the two previous conditions; and d) receiving KR in a yoked condition with self-controlled participants. In acquisition phase, motivational aspects, strategies for requesting KR and aspects related to the expectation of teaching were assessed according to each condition. Results: Participants with control over KR and/or with the expectation of teaching the skill showed superior learning of the task compared to the control condition. However, the combination of the experimental conditions did not result in additive learning benefits. Increased perceived competence was found in expecting to teach, self-controlled and combined conditions, compared to the yoked group. Additionally, expecting to teach also affected the way and the frequency learners requested KR. Conclusions: Our findings provide important insights toward understanding the effects of expecting to teach, in addition to demonstrating that expecting to teach affects self-controlled KR scheduling and its use during motor skill acquisition.

The Relative Age Effect in Male and Female Brazilian Elite Volleyball Athletes of Varied Competitive Levels.

Volleyball is a popular sport in Brazil, and the relative age effect (RAE) is known to occur within it; but less is known of how RAE relates to elite Brazilian volleyball players' age, sex, and competitive levels. We aimed to investigate RAE prevalence with data from two seasons of play among players in the Superliga A (2020/2021 and 2021/2022 seasons), and Superliga B (2021 and 2022 seasons) made available from the Brazilian Volleyball Confederation (CBV), the club's official website, or direct consultation with the CBV. After removing duplicate data, we grouped these 1,063 athletes by their dates of birth, sex, and competition level (Superliga A or B). We divided players' birth dates into quarters (Q1: January-March, Q2: April-June, Q3: July-September and Q4: October-December) and into semesters, and we performed chi-square (χ2) tests to investigate RAE prevalence according to the players' sex and competitive level. RAE was prevalent overall (χ2 = 33.198; p < .001), among males (χ2 = 24.48; p < .001) and females (χ2 = 11.23; p < .011). Regarding competition level, RAE was evident among males in both Superliga A (χ2 = 14.581; p = 0.002), and B (χ2 = 13.985; p = 0.003), and among females in Superliga B (χ2 = 9.204; p = 0.027), but not Superliga A (χ2 = 4.012; p = 0.26). Thus, the RAE phenomenon operated differently for male and female Brazilian volleyball players according to their competitive level. We discuss the implications of these findings.

Prevalence of the Relative Age Effect in Elite Brazilian Volleyball: An Analysis Based on Gender, the Playing Position, and Performance Indicators.

Athletes born closer to an arbitrary cut-off date are more likely to reach an elite level in sport, which is supported by a phenomenon called the relative age effect (RAE). It is important to determine whether this phenomenon is present in a sport to minimize this selection bias. This study aimed to investigate the prevalence of RAE in elite volleyball athletes, considering the influence of gender, the playing position (Setter, Middle, Libero, Opposite, and Outside Hitter) and the performance level (attack points, aces, and block points). The sample comprised 203 male and 193 female athletes competing in the Superliga A in the 2020/2021 season, which was equivalent to all of the teams of the championship. The data collection was performed during May and June, 2021. Athletes were organized according to gender, the playing position, and performance in the Superliga. For performance variables, athletes were separated based on the median value (90.0), and classified as high- or low-performance. Chi-squared tests were performed to verify differences between birth date distributions in relation to the aforementioned variables. Results indicated overrepresentation of relatively older male athletes (Q1 = 35.96%; Q2 = 27.59%; Q3 = 19.21%; Q4 = 17.24%), especially in Middles, Opposites, and Outside Hitters, regardless of their performance level. Considering females, no differences were found. Our findings suggest that RAE operates differently for men and women in elite Brazilian volleyball. The characteristics of the games played by male and female elite athletes may lead to different talent selection processes, affecting the likelihood of RAE prevalence.

Did the Absence of Crowd Support During the Covid-19 Pandemic Affect the Home Advantage in Brazilian Elite Soccer?

This study aimed to investigate the impact of crowd absence due to the COVID-19 pandemic on home advantage in Series A and B of professional Brazilian male soccer. Moreover, we sought to compare the home advantage between different competitive levels. Data from 2018 to 2020 Brazilian professional soccer championships (Series A and B) were analyzed, consisting of 2280 matches. The effect of home advantage was calculated in relation to the number of points won, the number of wins, goals scored and goals conceded. Our results indicated that home advantage was reduced in Serie A. Specifically, the 2020 (absence of the crowd) and 2019 seasons showed smaller home advantage compared to the 2018 season. On the other hand, Serie B analyses indicated no changes in home advantage over the seasons analyzed. The comparison of home advantage between competitive levels indicated higher home advantage in Serie A, exclusively in the 2018 season. In addition to the absence of fans, other changes occurred in elite sports due to the pandemic, such as changes in rules and the calendar. Considering that home advantage is affected by multiple interacting factors, it is important to investigate specific sports leagues across the world to determine which factors had the greatest impact on the advantage of playing home matches.

Relative Age Effect on Brazilian male elite futsal athletes according to playing position and performance by goals scored on Brazil National Futsal Leagues

Abstract Introduction: The relative age effect is prevalent in different elite team sports. However, little is known about this phenomenon in high-level adult male futsal players. Aim: The present study aimed to investigate the prevalence of relative age effect in Brazilian male elite futsal players, and its relationship with playing position and goals scored on Brazil National Futsal Leagues (BNFL) from 2016 to 2020. Methods: The distribution of birth dates, playing positions, and goals scored by male participants of the Brazil National Futsal Leagues were analyzed. Chi-squared tests were used to analyze the birth dates distribution based on quarters and semesters of the year, according to playing position (defender, winger, pivot, and goalkeeper) and scoring performance (high and low). Results: The overall analysis indicated that the relative age effect is prevalent on the pool of athletes analyzed. However, this effect was position-dependent, since relatively older athletes were overrepresented only in wingers and defenders playing positions. On the other hand, scoring performance was not associated with the relative age effect, since this effect was found in both performance levels. Conclusion: Relative age effects are prevalent in Brazilian male elite futsal athletes, especially for defenders and wingers. Considering the high level of competitiveness for spots in elite futsal teams, coaches and sports administrators must be educated about the prevalence of the relative age effect in this sporting context. This is necessary in order to reduce the inequalities generated by age categories based on arbitrary cut-off dates, which may reduce potential talent loss.

Relative Age Effect in Brazilian water polo: analysis of male and female athletes from U16 to senior categories

Abstract Aim: To investigate the existence of relative age effect (RAE) in Brazilian water polo athletes according to sex and age category. Methods: The birthdate of 574 Brazilian water polo athletes were organized according to the athletes' birthdates into quarters of the year (Q1, Q2, Q3, and Q4), and classified according to sex (male and female) and age category (U16, U18, U20, and senior). To verify the existence of RAE, the Chi-Square tests (χ2) were performed, and the effect sizes (ω) were calculated for each of the tests. We also calculated odds ratio (ORs) and 95% confidence intervals, setting the level of significance to 0.05. As post hoc analysis, multiple comparisons between quarters were performed, with Bonferroni's correction (significance level set to 0.0083 in these cases). Results: The results indicated an uneven distribution of birthdates for male water polo athletes (χ2 = 12.257; p = 0.007; ω = 0.173), with an overrepresentation of athletes born in the first (p < 0.006) and second (p < 0.002) quarters. When sex and age category were considered, male athletes presented uneven distributions in U20 (χ2 = 10.747; p = 0.013; ω = 0.345) and senior (χ2= 12.614; p = 0.006; ω = 0.383) categories. In females, no differences were found. Conclusion: We conclude that there is an uneven distribution of birthdates in male Brazilian water polo athletes, indicating the presence of RAE in this group.

Market value of Brazilian soccer players that played 2020 series A and B of the Brazilian championship: an analysis based on quarters of birth and playing position

Abstract Aim: The present study aimed to investigate the prevalence of RAE in soccer players from different positions in Series A and B in 2020 Brazilian soccer, as well as the impact of RAE on the estimated market value of these players. Methods: Data from 1080 male elite soccer athletes were analyzed. Athletes were grouped according to birth quarters: Q1 (January-March), Q2 (April-June), Q3 (July-September), and Q4 (October-December) and the competitive level (Series A or B). Chi-square tests (χ2) were performed to compare the birthdates' distribution of athletes according to a competitive level and playing positions. Kruskal-Wallis test was used to compare the market values of players born in each of the quarters of the year across competitive levels and playing positions. The significance level was set at 5%. Results: The overall analyses showed the prevalence of RAE in Series A and B, with an overrepresentation of athletes born in the first two quarters of the year. The RAE analysis based on playing positions showed different from expected distributions for forwards, midfielders, and defenders in Series A. In Series B, only midfielders showed a difference from the expected distribution. As for the market values analyses, no differences were found based on the athletes' birth quarters, regardless of competitive level or playing position. Conclusion: Our results indicate that, although RAE is prevalent in Series A and B of elite Brazilian soccer, it does not seem to influence players' estimated market values.

Relative age effects in elite Brazilian track and field athletes are modulated by sex, age category, and event type

Abstract Aim: This study investigated the Relative Age Effect (RAE) in Brazilian track and field athletes based on sex, age category (U-16, U-18, U-20, U-23 and senior), and event type (sprints/hurdles, middle distance, long-distance, jumps, throws). Methods: Data from 2.259 male and 1.776 female elite track and field athletes, ranked top-50 in events held by the Brazilian Track and Field Confederation in 2019 were analyzed. To determine RAE athletes were divided into four quarters based on their months of birth, considering January 1st the cut-off date. The influence of sex, age category, and event types in the pervasion of RAE in Brazilian track and field athletes was assessed through Chi-squared tests. Results: Athletes born closer to the cut-off date were more frequent than athletes born further from this date were in male youth categories. This effect reduced as categories increased, even reversing in the senior category. Finally, RAE was more frequent in events in which athletic performance relies more on strength, speed, and power, which is the case of sprints/hurdles, jumps, and throws. Conclusion: RAE is particularly prevalent in young male Brazilian track and field athletes, which indicates that many potentially talented athletes are overlooked in youth tryouts because they were born months away from the cut-off date. Policies that reduce the disadvantages faced by relatively younger athletes are warranted in order to avoid the loss of potential sports talents.

The relationship between relative age effects and sex, age categories and playing positions in Brazilian National Handball Teams

Abstract Aims: This study investigated the existence of Relative Age Effect (RAE) in the selection process of male and female athletes in the Brazilian national handball teams according to age categories (U-18, U-21, and senior) and playing position (wings, backs, pivots, and goalkeepers). Methods: In order to determine RAE, athletes were divided based on their months of birth; quarters Q1 (January-March), Q2 (April-June), Q3 (July-September), and Q4 (October-December). Data were collected from the official Brazilian Handball Confederation (CBHb) website and included the athletes that participated in training and/or competitions composing the Brazilian national teams from 2014 to 2018. To determine the RAE on playing positions, age categories of male and female groups were pooled. Chi-squared tests were performed to investigate the RAE. Results: An over-representation of players born in Q1 and Q2 in the U-18, U-20, and senior categories of male teams and the U-20, and senior female teams were found. In the male teams, as the age category increased, RAE decreased, but still existed. Such distribution was reversed in the female athletes, with a higher RAE magnitude in the senior category as compared to U-18 and U-21. Additionally, it seems that RAE is dependent on the playing position only for male athletes (wings and backs) whereas RAE was found for all playing positions in female athletes. Conclusion: Overall, RAE was found in Brazilian national handball teams, but its magnitude and form of manifestation seem to be influenced by sex, category, and playing position.

Focus of attention and online demonstration effects on temporal error and muscle activation / Efeitos do foco de atenção e demonstração online no erro temporal e na ativação muscular

Abstract The purpose of the present study was to examine whether there would be performance differences between external and internal focus of attention conditions and an online demonstration condition, and if these differences would be observed at a neuromuscular level through EMG analysis, in addition to traditional outcome measures. We hypothesized that under the demonstration condition participants would perform better than under external and internal focus conditions. We also hypothesized that demonstration condition would show smaller EMG activity than external and internal focus conditions. Furthermore, we hope to replicate the benefits of external focus in relation to internal focus, both in outcome and product measures. Six male participants performed a bilateral leg extension under internal focus of attention, external focus of attention and online demonstration conditions. Muscular contractions goal times were set for concentric muscle action (4 seconds) and eccentric muscle action (2 seconds). An electrogoniometer was used to record muscular activation (production measures), and temporal error was used to observe performance (outcome measures). Results showed that online demonstration condition obtained better performance than external focus condition and a reduced muscular activation. However, differences between internal focus and the other experimental conditions were not found. These findings advance in the understanding mechanisms underpining the focus of attention, such as proposed by Constrained Action Hypothesis.

Resumo O objetivo do presente estudo foi avaliar as diferenças no desempenho entre as condições de foco de atenção externo e interno e uma condição de demonstração online. Adicionalmente, se essas diferenças seriam observadas em um nível neuromuscular por meio da análise EMG, além das medidas de resultados tradicionais. Foi levantada a hipótese que sob a condição de demonstração os participantes teriam um desempenho melhor do que sob as condições de foco externo e interno. Também foi levantado a hipótese que a condição de demonstração apresentaria menor atividade EMG do que as condições de foco externo e interno. Além disso, esperava-se corrobora os benefícios do foco externo em relação ao foco interno, tanto nas medidas de resultado quanto de produto. Seis participantes do sexo masculino realizaram uma extensão de perna bilateral nas condições: foco de atenção interno, foco de atenção externo e condições de demonstração online. Os tempos de meta de contrações musculares foram definidos para ação muscular concêntrica (4 segundos) e ação muscular excêntrica (2 segundos). Um eletrogoniômetro foi usado para registrar a ativação muscular (medidas de produção) e o erro temporal foi usado para observar o desempenho (medidas de resultado). Os resultados mostraram que a condição de demonstração online obteve melhor desempenho do que a condição de foco externo e uma ativação muscular reduzida. No entanto, não foram encontradas diferenças entre o foco interno e as outras condições experimentais. Esses achados avançam no entendimento dos mecanismos que sustentam o foco de atenção, como o proposto pela Constrained Action Hypothesis.

Reliability of physical, physiological and tactical measures in small-sided soccer Games with numerical equality and numerical superiority / Confiabilidade das medidas de demanda física, fisiológica e tática em pequenos jogos com superioridade e igualdade numérica no futebol

Abstract The aim of this study was to investigate the physical, physiological (HR) and tactical demands of small-sided soccer games (SSG) with numerical equality (3x3) and numerical superiority (4x3). Eighteen male players of a soccer team played against each other both types of SSG, both played as two 4-minute bouts interspersed with 4-minute rest. Physical (distances, velocities and accelerations) and HR demands were recorded by a GPS system (15hz) and a heart rate monitor during SSG. The individual tactical behaviors proposed by the System of Tactical Assessment in Soccer were registered by an observer who analyzed the SSG videos. Reliability was verified calculating the intraclass correlation coefficient (ICC) and the absolute and percentage standard error of measurement (SEM and %SEM, respectively), both considering athletes’ individual scores in each SSG bout. As a result, higher number of variables related to physical and physiological demands presented significant ICC values, being classified as moderate to excellent in relation to variables related to tactical demands. Considering these variables that presented significant ICC values in both SSG, the SEM% values found for physical and physiological variables ranged from 3.0 to 42.0%, while those found for the tactical variables ranged from 31.6 to 75.0%. It could be concluded that several variables related to physical and physiological demands present moderate to excellent reliability. Differently, the majority of variables related to tactical demands were not reliable in both types of SSG.

Resumo O objetivo do presente estudo foi investigar a confiabilidade das demandas física, fisiológica (FC) e tática em configurações de pequenos jogos (PJ) em igualdade (3x3) e superioridade numérica (4x3) no futebol. Dezoito jogadores do sexo masculino de uma equipe de futebol jogaram entre si os dois tipos de PJ, com duas séries de 4 minutos e 4 minutos de pausa entre elas. Durante os jogos, as variáveis relacionadas à demanda física (distâncias, velocidades, acelerações) e fisiológica foram registradas utilizando-se um equipamento de GPS (15hz) e um cardiofrequencímetro. Os comportamentos táticos individuais propostos pelo Sistema de Avaliação Tática no Futebol foram registrados por um avaliador partir da análise da filmagem dos jogos. A confiabilidade das medidas foi verificada considerando os valores individuais de cada atleta em cada série de PJ, por meio do coeficiente de correlação intraclasse (CCI) e do erro padrão de medida absoluto e percentual (EPM e EPM%, respectivamente). Como resultado, um maior número de variáveis relacionadas às demandas física e fisiológica apresentaram valores de CCI significativos com classificação moderada a excelente em relação às variáveis relacionadas à demanda tática. Considerando as variáveis com valores de CCI significativos em ambas as configurações de jogo, o EPM% variou entre 3,0 e 42,0% para as variáveis físicas e para a FC, e de 31,6 a 75,0% para as variáveis relativas à demanda tática. Conclui-se que diversas variáveis relacionadas às demandas física e fisiológica apresentaram confiabilidade moderada à excelente. Diferentemente, a maioria das medidas relacionadas à demanda tática não foi confiável em ambos PJ.